Radio power-supply apparatus



2 Shuts-Sheet 1 Filed Jan. 1926 IN VEN TOR.

Jan. 22, 1929.- 1,699,523

P. z. susumu RADIO YOWER SUPPLY APPARATUS and Jan. 1926 2 Shuts-Sheet ,2

559 l l l Patented Jan. 22, 1929.

UNITED. STATES PATENT OFFICE.

CHICAGO,

ILLINOIS.

RADIO rowan-surety 'arrnnn'rus' Application filed January An object of the present invention is to provide a simple reliable and humless source of current supply for the vacuum tubes commonly used in radio sets, and similar apparatus.

A further object is to reduce tliepco'st of such apparatus by using one and the same rectifier element for transferring energy for both A or filament current-requirements of such vacuum tubes, and B or plate circuit requirementsthereof, assembling the elements in a compact shielded container.

A further object is to prevent hum due to electrostatic or electromagnetic linkage from the elements of the power unit and its connecting cables reaching the sensitive grid circuits of the connected radio apparatus supplied by the power unit. A further object is to prevent varlatlons in load on the power unit from caus ng undesired voltage drop, by compensating for increase in voltage drop with increase 1n current output.

A further object is to prov de an automatic switch means to connect abattery tothe same rectifier as is used for B supply requirements and to disconnect said battery therefrom when said rectifier is required for B output.

Reference is made to the accompanying illustrations, of which Figure l is a schematic diagram, and Figure 2 is a diagram showing the use of the relay switch 34 of Figure 1. v

A further object is to decrease the effective direct current impedance of such deyices to prevent audio regenerative feedback effects in the radio set connected to the power unit, due to the filter circuit resistance thereo A further object is to provide a reliable device of this class of small bulk and weight attachable to any standard type of radio set without requiring any changes in the wiring of'said set, whether said set is loop or aerial operated or uses different styles of vacuum, tubes with different current requirements. Eurtherj objects will presently appear and i specifically covered by the appendiithin the scope of which various nd' modifications may be made.

to a radio set using two or more stages of radio frequency amplification, a

pplying filament and plate circuit 8, 1926. Serial No. 80,112.

tube detector, and two or three ormore sta es of audio frequency amplification, it is ound necessary to shield the set from the power .unit' and to even shield the connecting cables to prevent transfer of energytherefrom to the sensitive grid circuits of the set, as accomplished by the present invention. It is also found necessary to reduce the effective resistance of the filter circuit used to prevent audio feedback effects thru the impedance thereof and this is accomplished by use of a shunt circuit in the output comprised by an electrolytic condefiser having favorable characteristics for such purpose.

As shown more particularly in Figure 1, which is a diagrammatic illustration of the invention, the invention will now be described in more detail.

The various elements presently to be described are contained in a shielded enclosure 6, preferably made from sheet 1ron, from which flexible shields 5 and 4 extend to house the output cable 7, 8, 9, 10, 11, 12 and input cable 3, 2 respectively. Shields 4 and 5 may comprise thin copper ribbon tape wound over said insulated cables. The entire apparatus is thereby shielded from the radio set 13 and may be located nearby.

The power unit 6 has means for connecting to a source of alternating current comprised by an attachment plug 1 to which wires 3 and 2 are connected to energize primary winding 56 of transformer 14, via resistance element (31. Resistance (31 contacts with a small portion of mercury 59 connected to contact 60 in a glass or quartz container 58 such that increase of current thru winding 56 and resistance 61 causes the mercury 59 to expand and reduce the length of resistance 61 not covered by mercury 59. Thus element 61 has its resistance reduced with increasingload on transformer 14 tending'to improve regulation thereof with different loads thereon. \Vhen the connected radio set 13 has smaller power requirements the extra tap 62 on primary 56 of transformer 14 can be used.

The middle tapped secondary 65 of transformer 14 connects to a rectifier element 63. This may be of any type but is preferably a Raytheon or helium gas type rectifier. Where desired two or more such lectifiers can be connected in parallel to increase the power of the unit but ordinarily one such rectifier element suflices where the B requirementsof set '13 are not over 50 milliamperes and the A requirements do not need a charging rate of over ampere for the battery 39. 64 indicates this parallel connected rectifier tube which is ordinarily not required. A switch 66 can cut out the regulator resistance 61 when the unit is used on output and input requirements which do not var A sheet iron shield 67 encloses the trans ormer 14 and rectifier element 63. Two small by-pass condensers of M. F. size, 15, 16, are connected across the cathodes 68 and 69 of rectifier 63 with their junction connectedto the tapped secondary 64 of transformer 14.

' .The output of rectifier 63 connects to a filter storage system contained in shielded enclosures of sheet iron 44, 45, 46. 44 contains the impedance coil 42 which may be 5 henry size. contains the impedance coil 72 and parallel condenser 74 tuned to be a frequency trap for the alternating frequency, as for 'example29 henrys and 6 M. Fpcapacity respectively. Container 46 includes a brute force type impedance coil of 30 to henr s size with condensers 79 and 80 of 2 M. or larger size. A resistance 'ma potential 0 the filter storage circuit comprised in containers 44, 45, 46 held in conta'iner 6. A regulator 50 may be cut in circuit by openin switch 75 .where required to' compensate 'or varying loads.

Regulator 50 comprises a resistance element 48 similar to resistance 61 but of higher resistance value, such. as an impregnated poor conductor strip well known in the art and including carbon or other poor conducting material.

Element 48 contacts with mercury 49 held in container 47 of quartz or glass and con-' nec'ts therethrough with contact 49. As current thru resistance 48 increases with increasing load drawn by set 13, mercury 49 expands and reduces voltage drop due to this increasing load, as same increases with the increase in current. Either one or both regulators 50 and 61 may be used as required.

A condenser 54 of about 6 M. F. size and a shunt regulator circuit 76 is connected to the output side of regulator 50. Shunt circuit 76 comprises electrolytic condenser cells 51, 52, 53 each made up from an aluminum and a lead electrode contacting with a solution of borax or sodium ammonium phosphate as is well known in the art. These cells 51, 52, 53 may be of small size as the current passing therethrough is very minute. The characteristics of such cells 51, 52, 53 are favorable and hum sounds due to impedance or resistance coupling of the circuits of set 13 thru the resistance of the storage filter circiut above described are be used to adjust the outputthereby avoided. Also the voltage drop of such cells 51, 52, 53 provides convenient taps for different potentials for detector tube requirements. .Wire 41 grounds the negative terminals of the filter storage system just described. All hum ripples are thereby revented from reaching radio set 13.

Res1stance77 shunting cell 53 permits the potential drop thereacross to be used as a and pulls armature. 37 to actuate switch 34.

If desired switch 34 can also be hand operated by knob 57.

Battery 39 connects to switch terminals 22 and 23 of mercury switches 25, 28 respectively. Normally the spring 33 on shaft 38 of switch 34 holds armature 37 tipped so that the mercury 26 makes contact with contact 22 and contact 21 while the mercury 27 in glass tube 28 closes contact 24 with contact 23. At the same time mercury 29 in tube 30 opens contact 31 away from con; tact 32. If desired switch 81 can be closed so that contacts 32 and 31 do not function. Contact 24 connects by wire 18 to the anode 70 of rectifier 63. Contact 21 connects via resistance 20 to negative terminal 19 of the transformer rectifier combination enclosed by shield 67. 20 may comprise an ordinary 40 or 50 Watt lamp or may comprise any other means to reduce the output potential from rectifier 63 to a value suitable for charging battery 39 via switch elements 25 and 28. As soon as switch 34 is turned by knob 57 or by armature 37 when coil 36 is energized, shaft 38 tips switch elements 25 and 28 to open contacts 21and 22 from each other and too en contacts 23 and 24 from each other, tiius disconnecting battery 39 from'charge connection to rectifier 63. At the same time, if switch 81 has been left closed or if not, then when mercury 29 closes switch contacts 31 and 32 to each other, current can flow from the rectifier anode 70 to the filter storage impedance coil 42. The switch element 30 can be omitted if desired by keeping switch 81 closed.

The function of the switch 34 is thus to disconnect the battery 39 from rectifier 63 while set 13 is being used, keeping alternating current fluctuations away from wires 17 during use of set 13, but permitting rectificr 63 to supply current to filter storage circuit comprised in containers 44, 45, 46. Then when switch 34 is turned either by fier 63 as set forth. Thus during use of set 13, the rectifier 63 supplies current to the filter storage system in containers 44, 45, 46 but energy is by-passed therefrom or diverted to charge battery 39 while set 13 is not in use. Battery 39 can thus be of smaller size than usual, say ampere hour size and is preferably of type using jelly electrolyte well known in the art. Switch 34 can have small dimensions because onl small currents are handled thereby. Sha t 38 thereof is supported on bracket 36 attached to core Shaft 38 carries the switch elements 25, 28, 30 containing mew cury arranged to make and break contacts as set forth. The operation is such that humless power supply is furnished to radio set 13 and battery 39 is maintained fully charged by continuous charge at all times set 13 is not used.

The power unit set forth is thus able to care for a variety of different sets with different current and voltage requirements and to make up for fluctuating loads thereof. It is well known that as a radio set 13 is tuned to different wavelengths and different conditions near resonance in its radio circuits, the plate current draw varies widely,

- being greatest at adjustment near oscillation resonance.

The increase in current required by set 13 causes the output potential supplied to its plate circuits to decrease. The increase in current however causes regulators 50 and 61 to function to compensate for this difference. The cable shields 4, 5 prevent electrostatic coupling to the radio set from the power circuits and shields 67, 44, 45, 46 serve to isolate each component enclosed from the other in this respect. Shield container 6 is further used to eliminate all ripple due to coupling effects from the power parts to the set 13. Switch 34 is preferably operated by magnet 36 automatically as set forth but can be hand operated if desired. Switch 81 can be omitted if switch arm 30 is used. This is preferable in that battery 39 is disconnected from rcctL fier 63 before the condenser 54 can be charged from the rectifier 63 thru the filter storage circuit in containers 44, 45, and 46. Cells 51, 52 and 53 have sufficient leakage resistance to discharge condenser 54 promptly before battery 39 is put on charge by. connection via switch 34 to rectifier 63. \Vhen coil 36 is used, the owner of set 13 can not forget to put battery 39 on charge as this occurs when set is turned off.

The use of mercury contacts prevents unreliable switch and contact operation due. to

corrosion which can occur on exposed switch parts.

I have built and operated a device of this kind and find that the objects set forth herein are accomplished thereby. On service with sets using only one or two stages of audio frequency amplification the shunt circuit 51, 52, 53 is not required, but on three stage sets this shunt circuit prevents audio regeneration as set forth.

The operation of relay switch 34 will be understood from Figure 2 which shows radio set 13 in use. Switch arm 82 of the rheostat of radio set 13 causes current to flow in .relay coil 36, thereby opening contacts 23 and 22 respectively from contacts 24 and 21 respectively, while contact 32 is closed to contact 31 so that rectifier-63 is operatively connected to plate filter 83. When rheostat switch arm 82 is moved to disconnect radio set 13 from batter 39, spring 33 restores relay switch 34 so t at battery 39 is charged via recititicr 63 as hereinbefore set forth.

I claim, and these Letters Patent are to be understood as granted for,

1. A radio power unit for supplying A and 13- electric current to vacuum tubes comprising, a battery, ,a rectifier element thru which current is passed to said battery during charge time thereof and thru which current is passed for said B current supply while said battery is not'being charged, a filter storage system connected to said rectifier element to transfer said B electric current therefrom, and a switch to'by-pass the output of said rectifier element to said batformer for boti A and B current re quiremcnts of vacuum tubes connected to said power unit, a filtercircuit connected to saidrectifier element and comprising means for supplying said B current. requirements, a switch to divert energy out )ut from said rectifier element from said filter circuit to said battery when it is not furnishing current for said B requirements and to disconnect said battery therefromwvhen said B energy supply is used, means to shield said elements to prevent the spread of leakage lines or tubes of force arising therefrom, a cable connected to said unit, and a shield for said cable.

3. A radio power unit comprising a metallic container. a supply cable and an output cable therefor, a shield on said cables, a transformer, a rectifier, a filter circuit and a battery in said container, and switching means to alternately connect said rectifier to said battery to divert the current from said transformer thru said rectifier thereto, and to disconnect said battery therefrom so that said rectifier will feed said filter circuit when said'battery is so disconnectedtherefrom.

4. A radio power unit comprising a trans former, means to connect said transformer to a source of alternating current, a shield for said connecting means, a rectifier connected to said transformer, a storage filter circuit connected to said rectifier, a regulator for the output of said storage filter circuit, a battery, means to connect said batte to said rectifier and divert energy there rom to said battery and to disconnect said battery from said filter storage circuit and rectifier when the said rectifier is required to feed energy to said storage filter circuit, a cable extending from said battery and said filter storage clrcuit and including a shield therefor, and a shielded container for said elements. v

5. As a radio power unit, in combination, means to supply energy to the plate circuits of vacuum tubes connected to said power unit at adjustable potentials comprising a transformer, rectifier, and filter storage circuit, a battery to supply current to the filament circuit of said vacuum tubes,,a series regulating resistance to connect said battery and said rectifier, and a switch to disconnect said battery from said rectifier when the filament circuit of said vacuum tubes is energized therefrom and to connect said battery to said rectifier when said filament circuit of said connected vacuum tubes is not so energized, thereby charging said battery from said rectifier.

6. A radio power unit comprising a trans-' former, connecting means for said transfor-v mer, a rectifier connected to said transformer, a filter storage circuit connected to said rectifier, a regulator comprised with said filter storage circuit to adjust the output potential. thereof, a battery, a resistance element,

a switch to alternately connect said battery to said rectifier thru said resistance and disconnect same therefrom, a container for said elements and shielding means comprised with said container to confine fields and tubes of force arising from the elements therein.

. 7. In a device of the character set forth, meansto supply A and B current supplies to vacuum tubes, an electromagnet e11- ergized by said A current supply, a battery contained in said means, and a switch to connect and disconnect said battery therefrom and thereto controlled by said electrocircuit, an expanding element connected to said resistance element to decrease the effective resistance thereof as the current flowing therethru is increased, a shunt circuit for the output of said filter storage circuit to decrease the effective direct current resistance thereof, a battery in said container, a switch to connect said battery to'said rectifier, means to reduce the output potential from said rectifier before said output reaches said battery, means comprised in said switch to disconnect said battery from said rectifier when current is Withdrawn from said battery, and means to adjust the output potentials supplied by said power unit.

9. In a device of the character setforth,

a transformer with means to connect same to improvement in means for supplying both plate and filament current supplies for vacu-- umtubes which comprises apparatus including a common rectifying unit for supplying energy to charge a filament supplybattery while said connected vacuum tubes are not operated thereby, and for supplying plate energy thereto when operated. by said battery, and a switch therefor to by-pass the output of said rectifying unit from supplying said (plate energy to charge said battery when sai vacuumtubes are not in use. 11. In a device of the character set forth, a current supply apparatus including a transformer, a rectifier circuit and a filter circuit therefor, and a regulator for the output of said apparatus to compensate for the voltage drop as the output current is increased, comprising means to increase the input potential supplied to said filter circuit controlled by said increase in output current.

12. In a device of the character set forth, a current supply apparatus including a transformer, a rectifier, and a filter circuit, a regulator to control the output potential thereof operated by current supplied thru said transformer, and means to decrease the effective resistance of said circuit comprising one or more electrolytic cells connected in shunt to the output terminals of the filter circuit to divide the output potential thereof in a plurality of output sections.

13. In a radio power unit, means to convert alternating current to direct flowing current, a plurality of filter sections therefor, and an individual shield enclosing each said filter section and obstructing the linkage of lines of force between said filter sec tions' characterized by the fact that the polcntial of the output terminal filter section thereof is controlled by means actuated by the current flowing thru said filter sections.

14. In apparatus of the character described, a radio receiving set, an alternating current rectifier for s-ru ')plying direct current to the vacuum tubes of said receiving set, a relay controlling, said rectifier for operative- 1y connecting and disconnecting said direct current supply from said radio receiving set, a manual switching means for operatively and circuit connections for said relay controlled by operations of said manual switching means for correspondingly operatively connecting and disconnecting the direct current supply from said recti er and said radio receivlng set.

- In Witness whereof I have this 7th day of 20 January, 1926, hereunto set my hand.-

' PHILIP E. EDELMAN. 

